We found this circuit in a 1956 Sylvania publication. It serves to monitor telegraph transmissions being placed next to the transmitter. The circuit is indicated for the range of 80 and 160 meters.
This code switch was found in a 1990 Electronics Handbook. It can be mounted with BC558...
In this application we use an additional input circuit to enable the logic command with keys,...
This circuit was suggested by Signetics in 1980s documentation. The circuit makes use of the...